WO1986000680A1

WO1986000680A1 - Ball valve and method of mounting such valve

Info

Publication number: WO1986000680A1
Application number: PCT/DK1985/000067
Authority: WO
Inventors: Anders Niels Hansen
Original assignee: Broen Armatur A/S
Priority date: 1984-07-11
Filing date: 1985-07-10
Publication date: 1986-01-30
Also published as: DK341884A; DK158016C; DK341884D0; EP0188559A1; DK158016B; US4709902A

Abstract

The valve member (8) of a ball valve is retained in the valve housing (1) of the valve between an annular seal (21) and an annular retainer (22) which is mounted through one of the branches of the valve housing. The annular retainer (22) is secured in the valve housing (1) by being pressed into said housing and in the valve housing projecting means (23) are provided for engaging the annular retainer. A well defined and optimum sealing pressure is achieved between the valve member (8) and the annular seal (21). According to a method of mounting the valve, the retainer is pressed through a branch and beyond projecting engagement means until the pressing-in force reaches a predetermined value corresponding to the sealing pressured aimed at.

Description

Ball valve and method of mounting such valve .

This invention relates to a ball valve of the kind compris¬ ing a valve housing in which the valve member of the valve housing is retained between an annular sealing member and an annular retain- ing element mounted through one of the connecting branches of the valve housing .

Ball valves of the kind referred to above are known where¬ in the annular retaining element is screwed into contact against the valve member so as to press the valve member against the annular sealing member with a sealing pressure. However, by the previously known ball valves of this kind it has proved to be difficult to secure the optimum sealing pressure between the annular sealing member and the valve member. It has been proposed to provide the annular retaining element and the valve housing with cooperating abutments which engage upon termination of the screwing-in of the annular retaining element, whereby it should be possible to obtain a wel l defined sealing pressure between the valve member and the annular sealing member . However, due to unavoidable tolerance variations during the manufacturing of the valves it is not possible by means of such a valve to secure an optimum sealing pressure .

As regards the prior art reference is also made to US patent specification No. 2.373.628 , from which a ball valve is known , the seats of which consist of rings of molded elastomeric material . I n each seat ring a spring insert is embedded having radial ly projecting fingers . When mounting the seat rings , the fingers are arranged with snap-action in circumferential ly extending grooves in the valve housing . However, also in this case tolerance variations during the manufacturing of the valves wi l l cause unequal sealing pressures between the valve member and the seat rings . The ball valve according to the present invention is cha¬ racterized by the annular retaining element being secured in the valve housing by being pressed into the housing and by projecting means being provided in the valve housing for engaging the annular retaining element. Hereby a very wel l defined pressure of abutment is achieved between the valve member and the annular sealing mem¬ ber which is independent of tolerance variations from valve to valve. When the annular retaining element is pressed into the valve housing until the force with which the pressing is carried out has achieved a predetermined value, the annular retaining element wil l maintain the valve member pressed against the annular sealing member with a well defined pressure of abutment, and accordingly the optimum seal ing pressure between the valve member and the annular seal ing member may be achieved .

Preferably, according to the invention the projecting means comprise a circumferential I y extending ridge, seeing that such a ridge is easily manufactured , e . g . by turning . I n order to facilitate the pressing of the annular retaining element into the valve housing the ridge preferably according to the invention comprises a sloping surface facing away from the valve member and a steep surface facing the valve member . The latter surface wil l secure the retaining element in the pressed-in position . According to a further embodiment of the invention the steep surface- may be- positioned in a plane, which extends perpendi¬ cular to the axis of the annular retaining element. Thereby a parti¬ cu larly well defined securing of the retaining element is obtained .

Preferably, according to the invention the ridge has a sharp edge in order to secure immobility of the retaining element after the pressing-in thereof .

A further embodiment of the invention is characterized by the annular retaining element consisting of a single piece of a compa¬ ratively hard material , e . g . a mixture of suiphonated plastic and teflon reinforced by fibres . Due to the manufacturing of the retain¬ ing element in one piece a simple embodiment is obtained and a material of the kind referred to or a corresponding kind has proved to be appropriate due to the fact that such material has a somewhat "slippery" character, and accordingly offers only a small resistance during the pressing-in of the retaining element.

The invention also relates to a method of mounting a bal l valve comprising a valve housing , wherein the valve member of the valve is retained between an annular sealing member and an annular _t retaining element which is introduced through one of the branches of the valve. According to the present invention the retaining element is pressed through the branch beyond projecting engagement means until the pressing force reaches a predetermined value corresponding to the sealing pressure aimed at.

The invention will hereinafter be further explained with reference to the drawings, on which

Fig. 1 shows an axia ly extending section through an embodiment of the ball valve according to the invention having branches with soldered pipe pieces, Fig. 2 shows a section according to section line 11 -I I in

Fig. 1, fig. 3 shows a picture corresponding to Fig. 1, but without pipe pieces, Fig. 4 shows an axially extending cross section of another embodiment of the ball valve according to the invention, and Fig. 5 shows an axially extending cross section of a still further embodiment of the ball valve accord¬ ing to the invention. On the drawing, 1 designates the housing of the valve shown. The housing is manufactured from a hexagonal bar, and is provided with two branches 2 and 3 which according to the embodi¬ ment illustrated in Figs. 1-3 have smooth inner surfaces for solder¬ ing pieces of pipes 5 and 6 which as mentioned have been omitted in Fig. 3.

The valve plug or member of the ball valve is provided with the reference numeral 8 and consists of a head 9 which by means of a neck 10 is connected with a generally spherical part 11 according to the embodiments illustrated in Figs. 1-4. In the spheri¬ cal part 11 a flow passage 12 is provided and, accordingly, it will be seen that the valves have been shown in their open position. The head 9 is by means of a O-ring 15 sealed with respect to a side opening in the valve housing 1, the wall of the side open¬ ing being provided with the reference numeral 16. According to the embodiment illustrated in Figs.1-3 this opening has such a size that the spherical part 11 may pass through the opening, and the head 10 has a corresponding size. Thereby the valve member which is made in one piece may be mounted by being inserted through the side opening. At the end of the valve member 8 facing away from the head 9 the valve member is provided with a projection 17 shaped as a convex lens which extends into a recess 18 in the valve housing . The projection 17 and the. recess 18 are shaped in such a way that they al low a rotation of the valve member 8 from the open position illustrated on the drawing and to closed position , viz. rotated 90 with respect: to the position shown . Accordingly, the projection 17 and the recess 18 form end stops for the movement of the valve member. A blind hole 20 having engagement surfaces for a corres- pondingly shaped tool is provided in the head 9 for rotating the valve member .

The valve member 8 is retained in the valve housing between an annular sealing member 21 and an annular retaining element 22. The sealing member 21 is positioned in a recess 24 which faces towards the valve member 8. The retaining element 22 is pres¬ sed into the valve- housing, viz . in the- case concerned through the branch 3.

I n order to secure the annular retaining element 22 after the pressing-in thereof, the valve housing is internal ly provided with projecting means which according to the embodiments shown on the drawing are shaped as a ridge 23. The surface of the ridge 23 facing away from the valve member 8 slopes conical ly outwardly in direction away from the valve member 8 whereby the pressing-in of the annular retaining element 22 is facilitated . The surface of the ridge 23 facing towards the valve member 8 , on the contrary, is steep and extends according to the embodiment shown on the draw¬ ing in a plane extending perpendicular to the axis of the annular retaining element 22. Thereby the retaining element is secured in the inserted position thereof , because the ridge 23, as seen in cross section , acts as a pawl or as a barb . The securing of the retaining element 22 is according to the embodiment il lustrated fu rther suppor¬ ted in that the ridge 23 has a sharp edge .

I n Fig . 4 the same reference numerals are used for the embodiment illustrated therein as in Figs . 1 -3 in al l instances where the same or equivalent parts are concerned .

It wil l be seen that the differences between the embodiment according to Fig . 4 and the embodiment according to Figs . 1 -3 general ly consists in that the valve member 8 in Fig . 4 is provided with a head 9 having a considerably shorter radius than the spheri¬ cal part 11 , viz. in such a way that the valve member after the mounting of the annular sealing member 21 , but before the pressing- in of the annular retaining element 22 may be mounted through the branch 3 with the head pointing forward whereafter the valve mem¬ ber may be arranged in the final^" position by rotating the valve member and simultaneously inserting the head into the side opening 16 from the inside . Moreover, the branches 2 and 3 are according to Fig . 4 provided with threads , viz . one external and one internal thread . However , it will be understood that any other sort of thread combination may be used . Furthermore, the head 9 of the valve member 8 in Fig . 4 is provided with a notch 26 for engaging a screw driver for rotating the valve member . For the embodiment illustrated in Fig . 5 the same reference numerals have been used as in Fig . 4 as regards al l the instances where similar or equivalent parts are concerned .

It wil l be seen that the differences between the embodi¬ ments according to Figs . 5 and 4 general ly consist in that the valve member 8 in Fig . 5 consists of two parts , viz . the head 9 and the spherical part 11 which in the mounted condition of the valve are mutual ly connected in a non-rotatable way , seeing that a notch 29 is provided in the spherical part 11 , wherein a rib 30 on the lower surface of the head 9 engages . Moreover, along the internal end of the side opening 16 a recess 31 is provided , and the head 9 is at its lower side provided with a corresponding shou lder 32 which engages the recess and , accordingly, prevents the head 9 from slipping out of the side opening 16. According to this embodiment the head 9 is mounted from the interior in the side opening 16 after having been moved throught one of the branches and is arranged with the rib 30 extending parallel with the longitudinal direction of the valve before the mounting of the retaining element 22. Then the spherical part 11 is inserted through the branch 3 with the notch 29 extending paral ¬ lel with the longitudinal axis of the valve until abutment against the sealing member 21 is obtained , and with the notch 29 engaging the rib 30. Then the annular retaining element 22 is mounted .

According to the embodiments illustrated on the drawing the annular retaining element 22 consists of a single part and is produced from a comparatively hard material , but however, not har¬ der than the material allows the deformation necessary for the pres- sing-in of the retaining element. As an example of a material suitable for the retaining element 22 a mixture of a sulphonated plastic and teflon reinforced by means of fibres may be mentioned . However, it will be understood that many other materials may be used having generally corresponding conditions .

The valves shown on the drawing are mounted in the fol lowing way:

After the positioning of the valve member 8 in the valve housing 1 the annular retaining element 22 is inserted through the branch 3 until the side of the retaining element facing towards the valve member 8 abuts the ridge 23. Now a certain pressing force wil l be necessary in order to press said side of the retaining element beyond the ridge 23. The force necessary in order to press said surface or the front surface of the retaining element 22 beyond the ridge 23 is very wel l defined because both the ridge 23 and the outer surface of the retaining element 22 which is cyl indrical , may be produced within very narrow tolerances . By further pressing-in of the retaining element 22 a seat 27 on the retaining element wil l contact the spherical part 11 and press the opposite side thereof into contact with a seat 28 on the seal ing member 21 . Now the resistance against the pressing-in of the retaining element 22 wil l increase, viz . proportionally with the increase of the contact pressure between the valve member and the sealing member 21 . Empirical ly a final force for pressing in the retaining element may now be determined which results in an optimum sealing pressure between the valve member 8 and the sealing member 21 without clamping the valve member too hard , and when this pressing-in force is achieved the pressing-in is stopped . This seal ing pressure wil l be independent of whether smal l differences exist from valve to valve due to the tolerances used during the manufacturing , e. g . as regards the distance from the recess 24 and to the ridge 23, the axial thickness of the sealing member 21 , the diameter of the spherical part 11 and the length of the part of the retaining element 22 which has been pressed beyond the ridge 23. Moreover, due to the fact that the force necessary in order to press the retaining element 22 past the ridge 23, as ex¬ plained previously, generally will be constant from valve to valve, the ratio of the final pressing force applied to the retaining element 22 to the final sealing pressure between the valve member 8 and the sealing member 21 will be well defined .

Claims

Patent Claims.

1. Ball valve, comprising a valve housing (1) in which the valve member (8) of the valve is retained between an annular sealing member (21) and an annular retaining element (22) mounted through one of the connecting branches of the valve housing, c h a a c¬ t e i z e d by the annular retaining element (22) being secured in the valve housing (1) by being pressed into the valve housing, and by projecting means (23) being provided in the valve housing (1) 0 for engaging the annular retaining element (22).

2. Ball valve according to claim 1, c h a r a c t e r i z e d by the projecting means consisting of a circumferentially extending ridge (23).

3. Ball valve according to claim 2, c h a r a c t e r i z e d ₅ by the ridge (23) comprising a sloping and away from the valve member (8) facing surface and a steep surface facing towards the valve member- (8) and a steep surface facing towards the valve mem¬ ber (8).

4. Ball valve according to claim 3, c h a r a c t e r i z e d 0 by the steep surface being positioned in a plane which extends perpendicular to the axis of the annular retaining element (22).

5. Ball valve according to claim 4, c h a r a c t e r i z e d by the ridge (23) comprising a sharp edge.

6. Ball valve according to claim 1, c h a r a c t e r i z e d 5 by the annular retaining element (22) consisting of one piece and of a comparatively hard material as e.g. a mixture of sulphonated plastic and teflon reinforced by fibres.

7. Method of mounting a ball valve according to claim 1, comprising a valve housing wherein the valve member of the valve is Q retained between an annular sealing member and an annular retaining element which is introduced through one of the branches of the valve, c h a r a c t e r i z e d by the retaining element being pressed through the branch and beyond projecting engagement means until the pressing-in force reaches a predetermined value correspond- 5 ing to the sealing pressure aimed at.